Hey Mike,
You need to use the alias method and tell it what to call the alias.
So, you'll want something like this:
service_table = Arel::Table.new(:service)
s1 = service_table.alias("s1")
s2 = service_table.alias("s2")
Take a look at the inner query of this (relevant_contents_query):
https://gist.github.com/22966422d5a62b100d96
Cheers,
Chris
On Tue, Jul 5, 2011 at 5:15 PM, Mike Bailey <[email protected]> wrote:
> I have a working SQL query I'm trying to convert to Arel. I'm trying to work
> out the syntax for a self referential join on a table.
>
> I can't work out how to address the table as 's1' and 's2' so my query makes
> sense.
>
> irb(main):018:0> s1.join(s2).on(s1[:serviceid].eq(s2[:serviceid]),
> s1[:id].gt(s2[:id])).where(s2[:serviceid].eq(nil)).to_sql
> => "SELECT FROM `service` INNER JOIN `service` ON `service`.`serviceid` =
> `service`.`serviceid` AND `service`.`id` > `service`.`id` WHERE
> `service`.`serviceid` IS NULL"
>
> Has anyone done this?
>
> - Mike
>
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